GPS Logger

LCD Drivers
Copyright © 2011 Ktulu.

Feel free to use my photos, any part of sourcecode or schematics, but please mention me as the original author.
Room thermostat with colour  LCD
Gas boilers are usually equipped with a simple sort of controlling element, but they regulate the amount of heating by measuring the water temperature inside the system. Without a proper room thermostat, that works on the principle of measuring the air temperature, is actually a waste of energy.
This project offers a very simple and cost efficient solution for that.
The heart of the unit is an 8 bit PIC16F74 microcontroller from Microchip.
It's main task is to constantly monitor the room temperature trough a 1–wire digital thermometer IC, a DS1820 from Maxim, and to switch a relay on or off, that controls the gas boiler accordingly.
The system also features a color LCD, which was removed from an old mobile phone, a few LED's, an LDR sensor for night mode and a couple of pushbuttons.

For correct operation of the LCD, a supply voltage of 2.9V is needed. I've used an LM317L voltage regulator and two resistors to achive this. For data and control lines, a few simple two resistor voltage dividers were used.
The PCD is made from testboard because the simplicity of the hardware.
The plastic case, some resistors and the LM317L voltage regulator were the only parts I payd for. The rest of the components are reused. The unit was mounted on the livingroom's wall by two screws with the right side facing towards the window, so the LDR could get enough light.

A few drops of hot glue can do miracles, especially when all the components and the front panel are made of plastic.
The two backlight LED's are connected in parallel with a piece of wire.
Software and functionality

          The software is written in MikroPascal.

Youtube video link
Complete Sourcecode